Fieldtrip api integration tests

[alaa-yahia]

No description provided.

[djgrant]

A few comments but otherwise lovely stuff :)

[djgrant]

What is the purpose of these last two assertions? My initial impression (might be missing something though) is that if the enrolment is removed from the DB that's us covered - the rest is just implementation details.

[alaa-yahia]

It is in the delete logic that is why I added them

   await enrollments(db).delete(enrollmentKey);
    await events(db).delete(enrollmentKey);
    await tasks(db).delete({
      name: `trigger:${enrollmentKey.course_id}:${enrollmentKey.username}`,
    });

[alaa-yahia]

But yeah there isn't any data on the tables tasks & events

[djgrant]

With a unit test you want to check that the code does all the things you expect it to – so you're looking inside the the app into the implementation. With an integration test, it's more about testing things at the edges e.g. imagine you don't know how the code works, rather you're just looking at it from the perspective of a user (or in this case an API user i.e. the web app).

So for this test, I've just run the web app and looked at how it interacts with the API. I can see that when I create an enrolment, the web app then makes an API request to /courses/js2 and the response contains the field enrollment (which I now realise is spelt incorrectly everywhere hahaha).

When I delete the enrolment, the /courses/js2 endpoint no longer contains that field. This is how the app knows that the user is no longer enrolled on the course.

It can also be be helpful to check if something is stored in the database (for example, when there isn't an API endpoint to reveal the change).

[djgrant]

I don't think these lines are hugely necessary. There is a scenario I can think of where an event is queued, then a user deletes the enrolment before the event is processed. In that case, it would make sense to have those rows deleted. This is an unlikely edge case that I wouldn't worry testing for.

await events(db).delete(enrollmentKey);
await tasks(db).delete({
  name: `trigger:${enrollmentKey.course_id}:${enrollmentKey.username}`,
});

[alaa-yahia]

With a unit test you want to check that the code does all the things you expect it to – so you're looking inside the the app into the implementation. With an integration test, it's more about testing things at the edges e.g. imagine you don't know how the code works, rather you're just looking at it from the perspective of a user (or in this case an API user i.e. the web app).

So for this test, I've just run the web app and looked at how it interacts with the API. I can see that when I create an enrolment, the web app then makes an API request to /courses/js2 and the response contains the field enrollment (which I now realise is spelt incorrectly everywhere hahaha).

When I delete the enrolment, the /courses/js2 endpoint no longer contains that field. This is how the app knows that the user is no longer enrolled on the course.

It can also be be helpful to check if something is stored in the database (for example, when there isn't an API endpoint to reveal the change).

I don't understand your point
Do you mean I should have tested the exact response from get /courses/js2 & delete /courses/js2 instead of checking if the enrollment table has the user & course details or not ?

[djgrant]

Not exactly. Yes, check the response e.g. status code. But also you want to check if the enrolment was in fact deleted. Did the intended effect take place?

How to do that? Check in database – one option. But then we're looking at the internals of the app. The more we inspect the internals the more brittle the tests become. What if we switch to DynamoDB? Now the test breaks. Good integration tests allow you to refactor code without having to change the tests.

A better approach is to make another API call to the appropriate endpoint to check that you the user is no longer enrolled. In this way you check that the effect took place, but do so using the interface (the API) that you are testing.

[alaa-yahia]

It is clear now..Thanks for explaining